1. Field of the Invention
The present invention relates to devices for producing electrical energy from mixtures of fuel (i.e., hydrogen and/or hydrogen-yielding fuel) and oxygen.
2. Description of the Prior Art
U.S. Pat. No. 4,863,813, issued to Dyer, discloses a solid electrolyte fuel cell capable of producing electrical current when exposed to an oxygen/hydrogen, oxygen/methane, or oxygen/methanol feed mixture. The fuel cell has a permeable outer electrode and an impermeable inner electrode. The electrodes are separated by an electron insulating, ion conducting, gas permeable solid electrolyte. The electrodes catalyze electrochemical half cell reactions which produce a surplus of electrons at one electrode and consume electrons at the other electrode. The inner electrode and the outer electrode of the Dyer fuel cell can consist of platinum, palladium, or an undefined alloy of platinum and palladium. Other suitable electrode materials include gold, nickel, and nonmetals such as electrically conducting mixed oxides with spinel or perovskite structure.
Although the Dyer device has been used to produce electrical energy from the fuel/oxygen mixtures mentioned above, the nature of the processes which causes the Dyer device to operate have heretofore been unknown. U.S. Pat. No. 4,863,813 states only that (1) the Dyer device depends for its operation on the ability to maintain different fuel:oxidizer ratios at the two electrodes and (2) these fuel/oxidizer concentration differences result from the differential diffusion of fuel and oxidizer through the permeable electrolyte. However, as explained hereinbelow, the Dyer device also depends for its operation on certain non-electrochemical reactions.